How can I render a tree structure (recursive) using a django template?

Question

I have a tree structure in memory that I would like to render in HTML using a Django template.

class Node():
  name = "node name"
  children = []

There will be some object root that is a Node, and children is a list of Nodes. root will be passed in the content of the template.

I have found this one discussion of how this might be achieved, but the poster suggests this might not be good in a production environment.

Does anybody know of a better way?

Answer 1

I think the canonical answer is: "Don't".

What you should probably do instead is unravel the thing in your view code, so it's just a matter of iterating over (in|de)dents in the template. I think I'd do it by appending indents and dedents to a list while recursing through the tree and then sending that "travelogue" list to the template. (the template would then insert <li> and </li> from that list, creating the recursive structure with "understanding" it.)

I'm also pretty sure recursively including template files is really a wrong way to do it...

Answer 2

this might be way more than you need, but there is a django module called 'mptt' - this stores a hierarchical tree structure in an sql database, and includes templates for display in the view code. you might be able to find something useful there.

here's the link : django-mptt

Answer 3

I had a similar issue, however I had first implemented the solution using JavaScript, and just afterwards considered how I would have done the same thing in django templates.

I used the serializer utility to turn a list off models into json, and used the json data as a basis for my hierarchy.

Answer 4

Django has a built in template helper for this exact scenario:

http://www.djangoproject.com/documentation/templates/#unordered-list

Answer 5

I had the same problem and I wrote a template tag. I know there are other tags like this out there but I needed to learn to make custom tags anyway :) I think it turned out pretty well.

Read the docstring for usage instructions.

http://jordanovski.com/a-recursive-django-template-tag

direct d/l link: http://jordanovski.com/wp-content/uploads/recurse.zip